A. Field of the Invention
The present invention relates to a new and improved flush valve for a toilet tank assembly.
B. Description of the Prior Art
One type of prior art flapper flush valve includes an integral planar body having a float member defined on one end. The valve is mounted in the tank assembly of a toilet with the float aligned with the flush valve seat of the assembly to control flow of fluid from the toilet tank. Prior art valves also include a device such as a chain that is connected to the float and to the lift arm in the toilet tank assembly to lift the flush valve in response to movement of the lift arm.
In view of the forces imparted to the body of the flush valve during lifting of the float member that can result in deterioration of the material of the body, typical integral prior art flush valves are fabricated from a soft elastomeric material of a low durometer hardness. Typical prior art valves of this type are disclosed in U.S. Pat. Nos. 3,702,012 and 3,707,733. This employment of a soft material in fabricating the flush valve prevents the fabrication of a lift strap integrally formed with the flush valve since the stresses and forces applied to the lift strap during operation of the toilet by movement of the lift arm result in rapid deterioration of the soft material of the strap. An example of one solution to this problem is illustrated in U.S. Pat. No. 3,158,873. However, this prior art valve is expensive due to the additional assembly steps necessitated by molding the lift string of this prior art valve into the outer coating of the float.